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Monday, April 30, 2012

- Some rain tonight, up to 1/2 inch- Temperatures surge to 75-80 degrees west of NYC tomorrow- Mild, mostly cloudy, few showers conditions linger through Saturday

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Mainly sunny skies were observed earlier today, with increasing clouds as a low pressure began to approach the region. Temperatures were once again below average, making this recent week the longest stretch of below average temperatures observed throughout the entire season; the previous longest consecutive stretch of below average temperatures was 7 days in late October into early November.

Tomorrow's Outlook:

Light to moderate rain will affect the area tonight into tomorrow, ending up locally heavy tomorrow morning, with at least 1/4 to 1/2 inch of rain expected for most places. The rain will end by at least 12 PM from NYC and further west and by 2 PM for Long Island/southern CT. Winds will start out from the SE, but switch towards the WNW/NW by the second half of the day.

Cloud cover is expected to clear from NYC and further north/west around at least 2-3 PM. With the warm air mass, clearing cloud cover, and WNW/NW winds, temperatures are expected to surge into the 70s in northern NJ, SE NY, NYC and western Long Island, perhaps getting into the upper 70s near NE NJ. For the temperature outlook, I sided close to the warmest models, although given the trends it is possible that the area may end up slightly warmer than expected. The temperature outlook gets more tricky going north and east of NYC, however, where the latest models continue to differ by as much as 10 degrees. I am siding with the slightly warmer solutions for tonight's forecast, with 60s for most of Long Island and southern/western CT, with upper 50s in eastern Long Island and eastern parts of Connecticut. The NAM model has been hinting at isolated thunderstorm development tomorrow evening in northern NJ; while this solution has little support from the other models, an isolated shower or storm cannot be ruled out west of NYC.

Forecast Overview:

With a back door cold front moving through New England and the area on Tuesday night, a cooler air mass will move in, keeping the area closer to average temperatures while southern parts of the region observe much warmer temperatures. Mostly to partly cloudy skies are expected on Wednesday and Thursday with highs generally in the lower to mid 60s from NYC and further north/west, getting into the upper 60s further west, and in the mid 50s to lower 60s for most of Long Island and southern CT. Thursday currently appears to be slightly cooler than Wednesday.

A warm surge is modeled to move through on Friday and Saturday, resulting in warmer temperatures especially west of NYC, although the extent of the warmth is still slightly uncertain and depends partially on the location of a cutoff low southeast of Newfoundland. At this time, I sided closer to the cooler models, with highs in the mid 70s to lower 80s from NYC and further north/west with highs in the 60s and 70s further east, although the outlook is still subject to change. Should the area enter the warm sector, scattered thunderstorms may be possible as well. The longer range is more uncertain, although temperatures are likely to cool down going into next week.

Yesterday (Saturday, 4/28) brought increasing clouds across the region as a wave of low pressure approached, remaining to the south of the area overnight. Due to the cold air mass in place, a widespread frost was observed inland, where temperatures dropped into the upper 20s to lower 30s in the far north/west suburbs of NYC. Places closer to NYC, including the city itself, saw low temperatures in the 30s, which is quite chilly for this time of the year; Central Park's 38 degree low was 11 degrees below the average low, and was 4 degrees short of breaking the record low for that date, set in 1934. High temperatures generally ended up in the upper 50s to lower 60s.

With the low pressure moving out, cloud cover has cleared for most places, and mainly sunny skies are expected through the rest of the day, with clear skies resulting in another frost potential tonight for interior parts of the area. A weak wave of low pressure will move through on Tuesday, bringing rain especially in the morning hours as a back door cold front moves through, keeping seasonable temperatures in place through Thursday as southern and western parts of the Northeast region surge into the 70s and 80s. Depending on the development of a potential Greenland block and the back door cold front, the surge of warmth may briefly reach the area on Friday; should it do so, temperatures may surge above 80 degrees, and thunderstorms may come back into the picture.

Today And Monday's Outlook:

Mainly sunny skies are expected to continue through today, with high temperatures reaching the upper 50s to lower 60s across the area again, getting close to 65 degrees in the immediate NYC area. A light NW wind is expected.

With clear skies tonight, cold temperatures are expected again with an inland freeze; temperatures will drop into the upper 20s for NW NJ, interior SE NY and possibly the colder areas of central/eastern Long Island, lower to mid 30s for southern CT and the rest of SE NY/northern NJ, mid to upper 30s for the immediate north/west suburbs of NYC, and the upper 30s to lower 40s in NYC.

Mostly sunny skies are expected for Monday morning, although cloud cover will increase by the late afternoon and evening hours as the next low pressure approaches. Temperatures will also reach the upper 50s to lower 60s for highs, getting close to 65 degrees in the immediate NYC area, with a light north wind in the morning becoming a light south wind by the afternoon.

Tuesday - Wednesday: Some Rain, Seasonable Temperatures

A weak wave of low pressure will approach the region on Monday, producing locally strong thunderstorms in western PA on Monday evening. The rain is expected to begin affecting the area after 12-2 AM, with scattered showers expected to last through at least 12 PM on Tuesday. Locally heavy showers are possible as well, with rain totals likely ending up close to 1/4 inch. Due to the cloud cover, occasional showers and an east/SE wind, chilly temperatures are expected, likely reaching the mid 50s in southern CT and Long Island, upper 50s to lower 60s in NYC, lower to mid 60s in the north and west suburbs of NYC, and the mid to possibly upper 60s towards NW NJ/Orange county. There is still uncertainty with the exact temperatures, the models continue to show different solutions, as the morning NAM run had highs in the mid 50s in NYC while the latest run has upper 60s, although given typical model trends, it is possible that the next update to the forecast may slightly increase high temperatures.

With the low pressure moving out, a back door cold front will be stuck close to the area, keeping New England chilly while the Mid Atlantic and western PA/NY end up with warmer temperatures. The area is expected to be in between this boundary, with temperatures ending up in the 60s for most places, possibly in the upper 50s towards southern Connecticut and in the lower 70s towards western NJ. Partly to mostly cloudy skies are expected on Wednesday, while scattered thunderstorms, locally strong, will take place towards Pennsylvania and the Mid Atlantic.

Thursday - Weekend: Brief Warm Surge / Storms Possible

Warmer temperatures may return on Thursday as a warm air mass moves into the region. While temperatures especially further east will still be influenced by an onshore flow, the western parts of the area are expected to reach and pass 70 degrees, with mid 70s possible towards western NJ. Isolated thunderstorms are also possible west of NYC; the best risk of scattered thunderstorms, however, is in Pennsylvania and New York, where storms could end up locally strong.

Depending on a developing block near Greenland, discussed in more details in the next paragraph, and the location of the warm sector, a one day warm surge may be possible on Friday, focusing in the western and southern parts of the region while also affecting parts of, if not most of the area. In locations where winds end up switching to the southwest/WSW with at least partly sunny skies, temperatures are likely to easily surge well into the 80s, getting close to 90 degrees southwest of NYC. At this time, I am thinking that temperatures in the area end up in the mid 70s to lower 80s, with eastern areas the coolest, although places west of NYC, in the warmer case scenario, may also surge well into the 80s. In places that end up in the warm sector, more instability is expected, and the risk of strong thunderstorms may be there in parts of the region, although exactly where this potential ends up is still uncertain. Stay tuned for more information on the late week outlook.

By the end of the week, strong ridging will push towards Greenland, with a Greenland block developing for the first time this season as a result. During the winter, a Greenland block would provide the East with below average temperatures and snow potentials, as observed during the winter of 2010-2011, although with shorter wavelengths as summer approaches, the impact won't be the same. A colder than average pattern is unlikely, especially as observed throughout April when despite some relatively strong troughs moving into the region, temperatures still ended up near-slightly below average as opposed to below-well below average. A persistently warm pattern, however, is unlikely as well, and as mentioned in my May outlook posted in the Long Range Forecasts page, most warm spells under this pattern are likely to end up relatively short lived, with slightly more frequent troughs keeping temperatures closer to average. More information will be posted on the May pattern as details become clearer.

Friday, April 27, 2012

- Freeze, Near Record Lows Expected Tonight- Below average temperatures last through early week- Significant warm up possible later next week

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Since the pattern changed in late March, cold air dropped into the region more frequently as blocking occasionally developed near Greenland, a factor which is needed for a cold pattern that has been missing basically the entire winter. The latest cold air mass dropping into the area is shaping up to have some of the biggest negative temperature departures of the season, as temperatures will drop into the 20s and 30s across the area tonight, resulting in a widespread freeze away from NYC, possibly even a hard freeze towards NW Sussex and Orange counties, and temperatures will even get close to the record lows, with Central Park's record low near 34 degrees in 1934.

The chilly temperatures will last through at least Monday, with scattered showers possible on Saturday night, perhaps even mixing with light snow well to the west of NYC if precipitation makes it north into the area. As the pattern becomes more zonal, however, a warm air mass will return into the region, with rising temperatures towards the second half of next week along with scattered showers and possibly thunderstorms.

Saturday - Monday Outlook:

Increasing clouds are expected throughout the day tomorrow with temperatures still below average, reaching the mid to upper 50s inland and the upper 50s to lower 60s across the area. Scattered rain showers are possible overnight with lows dropping into the mid 30s inland and the upper 30s to lower 40s across the rest of the area. Sunday and Monday will both include mainly sunny skies despite some cloud cover on Sunday morning, with highs reaching the upper 50s to lower 60s across most of the area.

Tuesday - Late Next Week: Warmer, Some Rain

Mostly cloudy skies are expected on Thursday as an area of scattered showers moves through the region, bringing the potential for amounts locally up to or above 1/4 inch. This does not appear to be any significant rain event, and is unlikely to remove the drought, which in still holding in place; according to the latest US Drought Monitor update on Thursday, the area is still under a moderate drought, with a severe drought still barely holding on in parts of southern Connecticut. While the drought is not expected to get much worse through the medium range, significant improvements are also not very likely as long as the latest outlook of no significant rain events through the medium range holds in place.

By the second half of the week, temperatures will warm up as a warmer air mass moves in, with widespread 850mb temperatures above 10C making this the biggest surge of warmth since April 16, when the area reached the upper 80s for highs. In this case, however, there will be more cloud cover with a risk of scattered showers/storms, likely keeping temperatures on the cooler side, in the 70s to lower 80s, although a day or two of temperatures surging to near or above 85 degrees cannot be ruled out IF the warmer case scenario verifies. Some blocking is expected to develop near Greenland in this time frame, and while it will not have any significant impact on the region in this time of the year as it would've had in January or February for example, the possibility is there that the warmth ends up more suppressed than currently modeled, keeping temperatures mainly in the 70s. Stay tuned for more information on the late week warmth potential.

- The widespread rain that was originally supposed to fall today did not end up verifying, as two separate areas of rain formed, one to the south of the area and the other to the north, but with very little rain in between. The models began to reflect this change last night, about 18-24 hours before the rain event. A few showers are expected tonight especially north of NYC, amounting to less than 0.1 inch.

- Mostly sunny skies are expected on Friday but with windy conditions, gusting up to 35-40 mph. Highs will reach the upper 40s to lower 50s inland and the lower to mid 50s across the rest of the area. Temperatures will cool down into the 30s overnight with upper 20s for interior areas, resulting in the possibility of frost and/or freeze further north/west from NYC.

- Clouds will increase late on Saturday with highs on Saturday and Sunday reaching the mid to upper 50s across the area. The wave of low pressure for the weekend is still there, although the trend is to keep the wave suppressed not too far to the south of the area so that the rain falls in the Mid Atlantic, as opposed to 2 days ago when the consensus was for the moderate rain to affect the NYC area. The NAM is the northern outlier by showing moderate rain and even interior snow, and is expected to trend towards the other models with a drier and further south storm. A few showers are possible for Saturday night with otherwise mostly cloudy to cloudy skies, clearing on Sunday.

- Temperatures will gradually warm next week, first into the 60s and later the 70s, although some scattered showers are possible towards the second half of the week. No significant rain is expected, although the rain and cloud cover may limit the extent of the warmth, either keeping temperatures in the 70s if there are more clouds and rain, or in the 80s if there is more sunshine and less rain.

Tuesday, April 24, 2012

Wednesday - Thursday: Partly to mostly cloudy skies are expected tomorrow with a risk of isolated showers. Temperatures will reach the mid 50s to lower 60s on Wednesday. A low pressure will move through the region on Thursday, resulting in cloudy skies and occasional showers with at least 1/4 inch expected. Temperatures are expected to reach the mid to upper 50s further east and the upper 50s to lower 60s from NYC and further west.

Friday - Weekend: As the low pressure moves into southeastern Canada while intensifying, a cold air mass from northern Canada will drop into the region, once again keeping temperatures cooler than average. Mostly sunny skies are expected on Friday with highs reaching the mid to upper 50s across the area, possibly getting near 60 degrees in the immediate NYC area. Clouds will begin to increase overnight and into Saturday, with highs on Saturday reaching the lower to mid 50s across most of the area, possibly getting into the upper 50s near NYC if there's enough sunshine.

A wave of low pressure will approach the region on Saturday. With the low in SE Canada, any approaching storm will not be able to track well to the north of the area, with the main favored tracks at this time either not too far to the south of the area, resulting in rain, or far enough to the south so that it does not rain, although most models currently point to the rain outcome. Especially given how the models overestimated suppression with this pattern in some cases, including March 31 which was the last snow event close to the area, I am currently siding with the northern outcomes. While some rain may fall during the day on Saturday, especially if the wave ends up faster than expected, most of the rain potential appears to focus on Saturday night into Sunday.

With the track likely south of the area, along with a relatively strong cool air mass in the region, snow may come into play once again for parts of the region. The GFS and DGEX currently show snow falling in northern Pennsylvania, while I am considering the 12z ECM as an outlier for showing snow as far south as NYC. The time of the year alone strongly argues against snow reaching NYC, with many parts of the storm required to end up in the right place for it to actually snow in the city, although there is a possibility that if there is enough cold air and precipitation, snow may fall in parts of Pennsylvania/New York state. Regardless of whether snow reaches the higher elevations of NW NJ or not, this appears to be a cold storm, with temperatures struggling to get out of the 40s for highs should the timing and location of the storm support rain during the day. Dry conditions will return for early next week with warming temperatures. Stay tuned for more information on next weekend's outlook.

Throughout the day yesterday and the overnight hours, the region was affected by one of the strongest storms of the entire season and the biggest storm since early December. As a low pressure moved up the coast from southeastern Virginia into NYC and north into New York state, widespread moderate to heavy rain fell, with rain totals ending up between 2.5 and 3.5 inches in Long Island and NYC, 2-4 inches in southern CT, and 1.5 to 3 inches in northern NJ/SE NY. Gusty winds were also observed, with a peak gust of 54 mph in La Guardia airport and 40-50 mph gusts across most of Long Island. The low pressure ended up noticeably to the east of the expectation, failing to track west of NYC, although the main impact in the area from this change was slightly weaker winds than expected and temperatures failing to surge into the mid-upper 50s west of NYC. Instead, temperatures today peaked in the lower to mid 50s from NYC and further west, and in the mid 50s to lower 60s in Long Island and southern CT.

Although the widespread rain moved out last night, the low pressure will continue to affect the region through tomorrow with mainly cloudy skies and isolated showers. Although the low pressure will move out by tomorrow night, widespread cloud cover, below average temperatures and occasional showers will stick around through the rest of the week and into the weekend as well as a weak low pressure moves through on Thursday, followed by another potential low pressure for the weekend.

Tomorrow's Outlook:

As the low pressure continues to slowly drift away from the region, mostly cloudy skies are expected with breezy SW winds with gusts generally reaching up to 30-35 mph. Highs are expected to reach the lower to mid 50s inland, mid to upper 50s in the immediate NYC area, and the upper 50s to lower 60s in Long Island and southern Connecticut. Isolated showers are possible at times, especially north and west of NYC.

Wednesday - Weekend: Chilly, Mostly Cloudy, Rainy At Times

With the low pressure moving out of the region, partly cloudy skies are expected for Wednesday with lighter winds, although isolated showers are still possible north and west of NYC. Temperatures will slightly warm up, reaching the mid to upper 50s inland and upper 50s to lower 60s across the rest of the area, which is still colder than average.

The brief clearing in the cloud cover won't last for long, however, as another weak low pressure moves through the region on Thursday. This low will be much weaker than yesterday's storm, with occasional showers expected throughout the day on Thursday into Thursday evening with at least 1/4 inch of rain possible. Temperatures will rise into the lower to mid 60s, possibly passing 65 degrees near the immediate NYC area. Some weak instability is shown on the models, and a few rumbles of thunder may not be out of the question when the cold front moves through in the evening.

The low pressure will then move into southeastern Canada, quickly intensifying while stalling for a short period of time. This will allow cold air to drop into the region once again, while suppressing any incoming storm tracks over the weekend so that any storm does not track too far to the north of the area. There is a general model agreement for some sort of a wave of low pressure for the weekend, although the intensity and location of the low are still uncertain, with some models showing a cold 40-45 degree rain for the area while others keep the rain south of the area. The models frequently overestimated the intensity of cold spells this season, and at this time I am siding with the northern outcomes where the storm ends up affecting the area with some rain and below average temperatures for the weekend. Currently, most models favor Sunday for rain, although the rain could also extend back into Saturday as the GFS and DGEX are showing, and the CMC is not far from. There is still some uncertainty for this time frame, however, including the location and timing of the storm potential for the weekend, with the possibility that the storm may entirely stay south of the area, and the forecast is still subject to some changes. The latest models do not show any significant warm spell approaching; should temperatures end up warming significantly, the earliest time frame possible for this would be into the first 7 days of May.

Sunday, April 22, 2012

Below, occasional updates will be posted on the significant coastal storm currently affecting the region.

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11:05 PM: Last Round of Heavy Rain

Heavier rain moved into the area over the last few hours accompanied by increasing winds, with LaGuardia airport currently reporting 41 mph wind gusts. The low pressure is currently near southeastern New Jersey with a minimum pressure near 990 mb and is moving north, which is noticeably to the east of the expectation from yesterday, when most models took the low either over New Jersey or through eastern Pennsylvania.

A band of heavy rain is currently located near NYC and western Long Island, and is moving to the NW. This will be the last widespread band of heavy rain from the storm, as a dry slot is expanding north, bringing an earlier end to the steady precipitation than expected, likely by 12-1 AM for NYC and further west. East of NYC, the steady precipitation will last a little longer before ending. After 1 AM, there will still be some rain though, with locally heavy showers possible especially to the east of NYC.

This is the last storm update for tonight. The next forecast will be posted on Monday evening.

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7:00 PM: Heavy Rain Approaching

Throughout the afternoon hours, a steady light to moderate rain continued to fall across the area as the rain associated with the low pressure became more widespread, expanding to the north and west. The low pressure is currently down to at least 992 mb near southeastern Virginia, and is slowly moving to the north. As the low pressure continues to intensify, the winds are becoming stronger and more widespread as well; a 58 mph gust was previously reported near Cape May Harbor in southern NJ, and gusty winds are also starting to affect coastal parts of the NYC area.

The latest radar posted above shows that the heaviest rain associated with the storm is currently near southern NJ along with windy conditions. This band of heavy rain will spread to the north over the next few hours, starting to affect NYC after 8-9 PM. Heavy rain and windy conditions will last through at least 2 AM, when the heavy rain will move to the north of the area. Locally heavy showers will still move through NYC and places further north/east through at least 4-5 AM, with isolated showers through the rest of Monday. Rain totals are still expected to end up between 2 and 3 inches across the area, with locally higher amounts up to 3.5 inch possible.

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2:45 PM: Rain Intensifying

Since last night's update, the low pressure off the Southeast coast began to move up the coast while intensifying, and is currently a 996 mb low south of North Carolina. Light rain developed across the area early this morning, and as the low pressure intensified, the rain also became heavier and more widespread, with a steady light-moderate rain currently covering the entire area. Rainfall amounts observed so far are generally under 1/4 inch.

The low pressure currently south of North Carolina will continue to intensify while moving north. As it becomes negatively tilted, the rain will begin to extend more towards the north and west as well, with heavier rain forming later this afternoon near the southeastern Mid Atlantic and expanding to the east and west while moving north. This area of heavy rain will affect the area between at least 8-10 PM and 2 AM, which is when the worst of the storm will take place. Gusty winds are also expected, with gusts peaking around 35-45 mph in the immediate NYC area and 40-50 mph in Long Island and southern CT. The rain will begin to weaken after 2 AM, with isolated showers and winds gusting up to 40-45 mph lasting through Monday and Tuesday. Rain totals are expected to end up between 2 and 3 inches across most of the area, ending up locally closer to 3.5 inches. Stay tuned for more updates throughout the afternoon and evening.

- One of the strongest storms this season to affect the region tomorrow, Monday- Up to 3-4 inches of rain, 50-55 mph wind gusts expected for NYC area- Unseasonably late snowstorm for Pennsylvania, flakes may reach NW NJ- Seasonable temperatures return this week

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Today's Observations:

As a slow moving cold front slowly approached the area, warm temperatures were observed today, peaking in the mid 70s to 80 degrees north and west of NYC, in the lower to mid 70s in NYC, and mid 60s to low 70s in coastal NYC, Long Island and southern CT. Cloud cover increased throughout the afternoon hours as the front approached, with thunderstorms, locally heavy, having affected the western parts of the area this evening. The weakening line of light-moderate rain is currently near north central NJ and slowly moving east, reaching NYC by 11:30 PM to 12 AM, but struggling to make it east of NYC.

As the cold front stalls east of NYC tonight, a low pressure currently near the southeastern US will move up the coast while intensifying and pulling in large amounts of moisture. By tomorrow night, this low pressure will intensify into one of the strongest storms of the season, with heavy rain and strong winds expected in the east side of the storm, including NYC, with an unseasonably late heavy wet snowstorm for western Pennsylvania, where as much as a foot of wet snow may fall. Near to below average temperatures will stick around through the rest of the week following the storm, with temperatures cooling down again towards next weekend.

Sunday - Monday: Strong Storm Brings 2-3+ Inches Rain, 50 MPH Gusts

Forecasting this storm over the last week was not very easy, as although models showed the possibility of a big storm early on, the idea of a large storm unfolding was questionable given the very dry pattern, with drought conditions present across the region, and the trend throughout the season for storms to remain relatively weak and progressive without much amplification. This storm marks a change in this pattern as a much more amplified set up is expected during this time frame with a strong, slow moving low pressure moving NNW through the region. At first, I questioned the big storm idea in my forecasts, and although the big storm idea was considered a reasonable possibility, as it became clear that this storm would end up amplified, it also was apparent that my original thinking of a more progressive storm following this winter's pattern would not end up verifying. With a weak, progressive storm out of the question, the region is about to observe one of the strongest storms of the entire season, with impacts ranging from heavy rain and flash flooding to strong winds and even heavy snow in some areas.

Storm Development: The low pressure that will become the strong coastal low is currently a 1002 mb low located off the western coast of Florida. As the southern stream and northern stream phase, the low pressure will intensify as it moves up the coast, deepening to about 996 mb on Sunday afternoon while near eastern North Carolina. At that time, there will be an area of heavy rain near the eastern Mid Atlantic extending up to southern NJ and Washington DC, with light to moderate rain covering the rest of the region except for northwestern areas. The low pressure will continue to move north from that point, with the rain expanding and spreading further north. With the low also intensifying, a tighter pressure gradient will develop with increasingly windy conditions developing near the New Jersey coast and spreading north.

The worst of the storm will take place on Sunday night across most of the region. The low pressure will slow down as it tracks through the eastern half of Pennsylvania, getting down to about 984-986 mb. Heavy rain will move up the north and eastern sides of the storm, spreading through the NYC area followed by New England. Windy conditions will also accompany the heavy rain, with gusts to 45-55 mph possible near coastal areas. Meanwhile, in the western side of the storm where cold air will be pulled in, the rain will begin to change over to heavy wet wind-driven snow near far western NY, the western half of Pennsylvania, and the higher elevations of West Virginia. As the low pressure slowly drifts north through the region on Monday, precipitation will weaken across the region, with some rain persisting in New England while moderate-heavy wet snow continues in the western parts of the region.

Forecast for NYC Area: Rain is expected to develop after at least 1-3 PM across the area. A band of locally heavy rain is likely to move through around the mid-late afternoon hours, with a possible short time frame with lighter rain around the evening. As the low pressure approaches, winds will steadily increase through the evening hours, with the peak of the storm expected to take place between at least 8 PM and 2 AM. During this time frame, heavy rain will fall, with rain rates up to 3/4 to 1 inch per hour possible. Strong winds are also expected, with gusts up to 40-50 mph in the immediate NYC area and 45-55 mph near coastal areas. The rain will weaken by 2-3 AM, with occasional showers and rising temperatures between 2 AM and sunrise.

Temperatures will peak in the first half of Monday in the upper 50s to lower 60s across the area with mainly cloudy skies for the rest of the day along with breezy winds, gusting up to 35-40 mph. Isolated showers will continue especially north/west of NYC, and it is not out of the question that snow flakes may mix with the showers on Monday night in NE PA and possibly in the higher elevations of NW Sussex county.

Regional Outlook: This will end up as the biggest storm across the region since early December, making it nearly 4 and a half months since the last significant storm in the region. Widespread moderate to heavy rain is expected for many places, with amounts near 2-3 inches, locally up to 4 inches, from the eastern Mid Atlantic up the Interstate 95 corridor and further west into Maine. For the NYC area, at least 2 to 3 inches of rain are expected as well, locally up to 4 inches. While the rain will help the region considering that New England is in a severe drought, too much rain at once will still cause some flooding, and especially with heavy rain expected in a short period of time, the dry ground may enhance any flash flooding.

Another notable part of the storm is the heavy wet snow associated with it. There have not been many snowstorms this winter, and if amounts end up near the latest forecasts, this may actually end up as the 2nd biggest snowstorm of the season; this would add to an already odd winter season, as both of the biggest snowstorms actually ended up outside of winter itself, in October and in April. Western Pennsylvania, New York and West Virginia may observe conditions similar to what interior parts of the NYC area saw during late October, with a heavy, wet wind-driven snow accumulating on trees full of leaves, which may result in widespread power outages and tree damage. Above, I posted a snow map for this storm; while it shows the general snow totals, accumulations will highly depend on elevation with this storm, and some places may see less than shown above while others see more.

Stay tuned for occasional storm updates tomorrow reflecting the updated forecasts as well as the observations on this storm.

Saturday, April 21, 2012

A line of scattered thunderstorms associated with a cold front, some of these storms locally heavy, is currently approaching the western parts of the area towards NW NJ and Orange County in SE NY. While these storms are not severe, they are capable of containing brief downpours. These storms will slowly move NE through northern NJ and SE NY through the rest of the evening and the early overnight hours, getting into NYC by at least 11 PM. The heaviest rain is expected west of NYC, where at least 1/4 inch of rain is expected, locally higher. The showers will struggle to make it east of NYC, with only isolated showers expected in most of Long Island and southern CT.

Stay tuned for a detailed discussion later this evening about tomorrow's significant storm and its impact across the region, including rain and snow maps.

As a cold front slowly approached the region with increasing clouds, a warm air mass continued to push in, resulting in another mild day for interior areas. Temperatures peaked in the lower to mid 70s inland, upper 60s to lower 70s in the immediate NYC area, and the mid to upper 60s in Long Island and southern CT. Another warm day is expected tomorrow away from the coast, although as the cold front reaches the area, unsettled weather will return, with the first significant rain event since early December expected.

Tomorrow's Outlook:

As the cold front continues to move closer, mostly cloudy to cloudy skies are expected tomorrow with south winds. The warmest temperatures are expected further north/west, with temperatures in northern NJ and SE NY peaking in the mid 70s to near 80 degrees. NYC will reach the lower to mid 70s, with mid 60s to lower 70s in Long Island and southern CT. Coastal areas will remain in the lower to mid 60s. Rain and thunderstorms, locally strong, are expected along the cold front in Pennsylvania during the evening, with these storms getting into northern NJ and SE NY by the evening and overnight hours but failing to get much east of NYC.

Sunday - Tuesday: Heavy Rain, Up To 3-4 Inches

The cold front is expected to stall to the east of NYC overnight and on Sunday with cooler highs, reaching the lower to mid 50s across the area. Meanwhile, a low pressure will intensify near the Southeast US as it moves north up the coast, reaching the region on Sunday night into Monday as it begins to turn north, then NNW cutting through New York state. This track, along with a lot of moisture associated with the storm, will result in significant rainfall for a large part of the region and even a significant snowstorm further west.

Storm Scenario: The low pressure is likely to end up near southeast VA/eastern NC on Sunday, slowing down a little as it moves north and intensifies, ending up near eastern NJ on Sunday night. A steady moderate to locally heavy rain will move up the coast, reaching NYC by the early afternoon hours, intensifying throughout the evening hours. The low pressure will continue to send heavy rain up the coast along New Jersey and into most of New England, with increasing winds across the region, especially in Long Island and New England. Temperatures will also rise east of the low pressure on Sunday night into Monday morning, with parts of New England rising late overnight into the lower 60s. Meanwhile, to the west of the low pressure, colder air will move in, resulting in precipitation changing over to a wintry mix for western PA, West Virginia, and western NY, followed by a changeover to moderate to heavy wet snow. At least moderate amounts of snow are expected in these areas, making this an unusual late April significant snowstorm for these areas. The low pressure will then move into New York state on Monday with weakening precipitation and increasing winds.

Forecast for NYC Area: Periods of moderate rain are expected to develop across the area around the early afternoon hours on Sunday, steadily intensifying throughout the afternoon and evening hours along with steadily intensifying winds, gusting up to 35-40 mph in the immediate NYC area and 40-50 mph in Long Island/southern CT. The heaviest rain is expected during the first half of the overnight hours, with lighter rain by Monday morning and isolated showers for the rest of the day. Temperatures will also rise late overnight as the low pressure moves through, reaching the upper 40s to lower 50s further west and the upper 50s to lower 60s further east. Overall, at least 1.5 to 3.5 inches of rain are expected, with amounts locally up to 4 inches possible. Stay tuned for more information on this storm.

Longer Range: The storm will slowly move out of the region, with partly cloudy skies and highs in the 50s on Tuesday. The rest of the week is likely to end up partly cloudy, with temperatures slightly warming up but still remaining near to below average, reaching the 60s for highs. Another light to moderate rain event may be possible towards the end of next week.

After yesterday's unexpected light rain, cloud cover cleared today with mostly to partly sunny skies observed. Temperatures were warmer as well, peaking in the upper 60s to mid 70s from NYC and further north/west and the upper 50s to mid 60s in Long Island and southern CT. Similar temperatures are expected again tomorrow and on Saturday, although an approaching cold front will bring back rain into the forecast for Saturday afternoon/evening, which will be followed by a coastal storm which, if most of the latest models verify, should be the first significant rain event for the area since early December.

Tomorrow's Outlook:

Mostly to partly sunny skies are expected across the area again tomorrow with south/SSE winds keeping coastal areas colder again. Highs will reach the upper 60s to mid 70s from NYC and further north/west, and the upper 50s to mid 60s in Long Island and southern CT.

Saturday - Tuesday: Significant Rain Event Likely

A cold front will approach NYC on Saturday, with mostly cloudy skies becoming cloudy by the afternoon, along with a line of moderate to locally heavy rain and thunderstorms expected. At least 1/4 to 1/2 inch of rain is likely with the cold front. The front is then expected to move offshore and stall east of NYC, with some showers likely on Sunday along with cooler temperatures, peaking only in the 50s to possibly 60 degrees.

As the cold front moves through the area, a low pressure will develop near the southeastern US and begin to move up the coast. There is still some uncertainty with the exact track of the storm depending on how much phasing takes place, although the majority of the models show enough phasing to pull the storm north and NNW, resulting in at least moderate, if not heavy rain for NYC and further north/east. Yesterday, there was still uncertainty regarding whether the storm would completely phase and make it up the coast, although the GFS and NAM models, which were east of the area yesterday, are trending west and stronger with the storm to show more rain across the area. The rest of the foreign models, the ECM, CMC and UKMET, are in agreement with an overall wetter storm than the NAM/GFS but still differ with the phasing, as the ECM pulls the storm over NYC and into Michigan, while the CMC and UKMET take it north into Canada. These differences have more of an impact on the forecast for Monday and Tuesday, although these models still support moderate to heavy rain for the area.

Most of the rain from the coastal low is expected to fall on Sunday night, with windy conditions also possible depending on the track of the storm. As the storm moves to the north, scattered showers are expected on Monday along with cloudy skies and temperatures peaking in the lower to mid 50s across most of the area. Overall, at least 1 to 3 inches of rain are possible from the storm, with the highest amounts further east, towards Long Island and southern Connecticut. The forecast is still not final yet, however, as there is still uncertainty with parts of the forecast which could change the outcome. Stay tuned for more information on this storm and its impact in the NYC area.

Today started out with partly to mostly cloudy skies across the area, although an area of showers in the Mid Atlantic unexpectedly crawled north into the area, resulting in cloudy skies for the rest of the day along with occasional light rain showers. Although skies will clear again for Thursday and Friday, the dry conditions will not last for long as the next rainstorm arrives on Saturday.

Thursday - Friday: Partly Cloudy, Mild

Clearing skies are expected tomorrow with SW winds and a warmer air mass, resulting in temperatures warming up into the upper 60s to lower 70s across the area. Partly cloudy skies will return again for Friday but with a SSE wind, keeping temperatures in the upper 60s to mid 70s from NYC and further north/west and the mid 60s to lower 70s in Long Island/southern CT.

Saturday - Monday: Rain Expected, Uncertainty With Scenario

By Saturday, a cold front will approach the area, with showers and thunderstorms likely towards the second half of the day, especially by the evening and overnight. The model guidance is still split regarding the next step, with the CMC bringing a coastal low right up the cold front along I-95, the 0z ECM was an amplified outlier taking the low pressure through Pennsylvania, the 12z ECM amplifies the coastal low resulting in snow for parts of the area, and the GFS is much weaker, bringing the cold front through with very little rain from the Sunday-Monday coastal low. As a result, it is difficult to make any high confidence forecast at this time when it comes to the Sunday-Monday coastal low potential; some models suggest that as much as 2-4 inches of rain may be possible, while at the same time it is possible that the low doesn't organize significantly and keeps most of the rain east of the area.

Given some models' bias of exaggerating amplification of storms, I am considering the 0z ECM and UKMET as outliers. At this time, my thoughts have not changed much, and I am still thinking that a somewhat more progressive storm moves up the coast, with moderate rain and possibly thunderstorms associated with the cold front on Saturday, followed by some more rain on Sunday into Sunday night and possibly Monday associated with the potential coastal low. As previously mentioned, however, there is still uncertainty regarding the development of the coastal low, and this forecast is still subject to change. Stay tuned for more information on this time frame.

Tuesday, April 17, 2012

- Mild, dry through Saturday- Next storm to approach for weekend, early week- First significant rain since winter possible

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A cold front moved through the area last night, with temperatures quickly rising this morning to the low 70s in parts of the area. Temperatures ended up peaking in the mid 70s inland and the upper 70s to lower 80s across the rest of the area. Temperatures will cool down for the rest of the week, dropping into the 60s tomorrow and the 60s and 70s through Saturday, although the dry conditions will not last for long, as what may be the first significant rain event since the winter months will affect the area on the weekend into early next week.

Wednesday - Friday: Dry, Mild

Mostly sunny skies are expected to continue tomorrow with light winds. High temperatures will reach the lower to mid 60s across the area. Mostly to partly sunny skies will continue through Friday with temperatures slowly warming up; Thursday is expected to reach the upper 60s to lower 70s across the area, with the warmest temperatures in the lower 70s in the immediate NYC area. Friday will be slightly warmer west of NYC and cooler east of NYC.

Saturday - Early Next Week: Heavier Rain Possible

As a cold front slowly approaches the area on Saturday, clouds will increase to mostly cloudy with scattered showers possible. Temperatures are uncertain depending on the location of the front, although with onshore winds, temperatures are expected to generally end up in the mid 60s to low 70s but are still subject to change. The warmest temperatures should stay away from coastal areas.

Meanwhile, a low pressure in the southern US will approach the eastern coast, with larger differences in the models regarding the interaction between the southern and northern streams. Some models, such as some of today's GFS runs and the 12z ECM, show less interaction, with occasional periods of rain amounting close to 1 inch, locally higher. The CMC and the afternoon GFS run, meanwhile, showed more interaction, with a strong low pressure moving up the coast, resulting in wind and heavy rain easily adding up to several inches, which would noticeably ease the drought. There are too many differences to nail down one specific scenario, although at this time I am thinking that the low pressure does come up the coast but does not end up as strong and amplified as some models show, with the potential for as much as 1 or more inch of rain for at least parts of the area. The timing of the rain is also uncertain, although it appears that most of the rain should be focused around Sunday, possibly into Monday. Stay tuned for more information on this storm and the forecast rain.

After mostly cloudy skies yesterday, cloud cover cleared this morning to mostly sunny, resulting in what easily became the hottest day of the year so far and an unusually warm day this early in the year. Temperatures surged into the upper 80s to lower 90s across northern NJ, SE NY and interior southern CT, with lower to upper 80s in NYC and lower 70s to lower 80s in Long Island and coastal southern CT. The wind direction ended up being more from the south/SSE than expected, which prevented places such as Newark and Teterboro in NE NJ from reaching 90 degrees. Temperatures in the 90s were also observed further north towards northern Connecticut and Massachusetts.

The heat was only here for one day, as a dry cold front will move through tomorrow, with temperatures dropping back into the 60s and 70s for the rest of the week through the early weekend. No rain is expected this week with a risk of a few showers on Saturday, although there is an increasingly strong signal on the models that a more notable rain event may take place towards Sunday and early next week, which if verifies would be the first notable rain event the area had since the winter months.

Tomorrow's Outlook:

As a cold front will move through the region, temperatures will end up cooler tomorrow although still warmer than average. Mostly to partly sunny skies are expected with highs reaching the lower to mid 70s across the area, with upper 70s in parts of the immediate NYC area.

The wind will switch to a NW direction tomorrow, gusting up to 25-30 mph, which combined with low humidity and the ongoing drought, will increase the risk of fire spread should any fire ignite. The National Weather Service in Upton issued a Fire Weather Watch for the entire area tomorrow. As seen last week with the Meadowlands fire, there is an enhanced risk of fires with this dry pattern.

Wednesday - Saturday: Mild, Mostly Dry

A cooler air mass will briefly move in on Wednesday, with highs in the upper 50s to mid 60s across the area along with partly sunny skies. Warmer temperatures will return on Thursday with partly sunny skies and highs reaching the upper 60s to lower 70s across most of the area. No rain is expected on both days.

On Friday, the next low pressure will approach, staying north of the area. As a result, south winds are expected, with highs rising into the upper 60s and 70s away from the coast, where temperatures will likely stay below the upper 60s. As a cold front slowly approaches, scattered showers may develop towards Saturday.

Sunday - Early Next Week: Rain Returns

Since the start of 2012, there have been very little notable rain events, with a lack of 1/2 inch rain storms observed over the last month and a half. The latest models are all showing a significant rain event for the area by Sunday into early next week but vary with the specific details; the ECM shows a big storm with heavy rain and gusty winds, the CMC shows moderate rain, and the GFS shows 1-2+ inches of rain but varies from run to run, for example showing heavy steady rain on its morning runs while spreading the rain throughout a few days on its 18z run.

During the winter months and the spring as well, the models frequently overestimated the intensity of storms in the long range, backing down on the storm intensity and the amount of cold associated as the storm approached the shorter range. This is especially true with the recent dry pattern, where several storms modeled to produce moderate rain ended up having either light rain or nothing. The set up in this case is more favorable for a storm to finally affect the area with at least moderate rain, although the big storm scenario shown on some models is still questionable, and at this time I am thinking that a somewhat more progressive and weaker storm moves through, still bringing the potential for moderate rain but perhaps not the widespread 1-2+ inch shown on some models. Stay tuned for more information on this time period and the potential storm.

Sunday, April 15, 2012

- Drought to persist this week- Wind to enhance any fire risk on Monday- Heat returns tomorrow; 90-93 degrees in NE NJ, NYC- Next risk of rain by next weekend

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Today's Observations:

After the trough stuck over the region for the last week moved out, southwest winds returned across the region, bringing in a warmer air mass, with high temperatures reaching the mid 70s to 80 degrees across most of the area with the exception of Long Island and southern CT, where temperatures were in the mid 60s to low 70s. A few showers fell last night across the area, although the showers were isolated and brought less than 0.1 inch of rain across the area.

With almost no rain observed last night, the drought will continue to persist throughout this week, with the next rain event only expected to affect the area by next weekend. Heat will briefly return into the region tomorrow, with an unusually early 90+ degree day expected for parts of the area, especially near NYC and NE NJ. Although the temperatures will cool down by the second half of next week, only isolated showers are expected, with the next possibility of widespread rain by next weekend.

Tomorrow's Outlook:

The low pressure that produced yesterday's large tornado outbreak in the central US will continue to move NE into the Great Lakes, bringing a short lasting yet strong surge of warmth into the region tomorrow, easily making tomorrow the warmest day of the year so far. Factors such as a breezy SW/SSW wind gusting up to 30-35 mph, mostly sunny skies, 850mb temperatures near 14-16C, and a dry ground are favorable for temperatures to end up very warm for tomorrow.

With the factors above, temperatures will quickly climb across the area tomorrow, peaking in the upper 80s to lower 90s in NYC, northern NJ, SE NY, and interior southern CT, with a maximum temperature of about 92-93 degrees. Coastal southern CT and Long Island will be cooler, with highs in the lower to mid 80s except for the immediate coast, where temperatures will be in the 70s.

This early in the year, 80+ degree days are infrequent, and 90+ degree days are even more uncommon; the most recent 90+ degree day in the first half of April was in 2010, when parts of the area reached the low-mid 90s. If temperatures end up reaching 90 degrees in parts of the area as expected, tomorrow will end up as an unusually early 90+ degree day, and maybe even one of the earliest 90+ degree days on record for the NYC area.

Tuesday - Friday: Colder, Still Dry

The cold front will approach the area on Monday evening with thunderstorms in western PA and NY, but as frequently observed throughout this dry pattern, the rain will dissipate before reaching the area, and a dry cold front will move through around Tuesday with only partly cloudy skies. Temperatures are expected to reach the mid 70s across the area, with upper 70s near the immediate NYC area, with WNW winds.

A cooler air mass will return for Wednesday and Thursday, with highs dropping into the 60s again. An increase in cloud cover is possible on Thursday, but otherwise dry conditions will continue. By Friday, some showers could be possible, but again no widespread moderate rain is expected, instead more likely to end up as isolated showers. The temperature outlook is uncertain, depending on an approaching low pressure, but at this time I am siding with the warmer models, with highs ending up in the upper 60s and 70s across most of the area.

Next Weekend: Rain Expected, Amounts Still Uncertain

Since last night, the models have been in agreement with showing a large low pressure over the region for the weekend, with most of these models also showing a widespread heavy rain event, including the area, and trying to bring snow into the picture in the Northeast. The models have already exaggerated rain events in the medium and long range before, as a few days ago, this upcoming Wednesday for example was shown on some models to bring heavy rain instead of the partly sunny skies now expected, and even last night was originally modeled to bring 1/4 to 1/2 inch of rain instead of isolated showers. While at least some rain is expected over the weekend, and there is a better chance of seeing moderate rain than the last few storms, a large soaking rain event to ease the drought at this time remains questionable given the pattern and trends. There is more uncertainty going into the long range due to the time range, although cooler temperatures also appear to return by the weekend possibly going into early next week.

Friday, April 13, 2012

The 5-Day Forecast page has been updated for the immediate NYC area through Tuesday night. The next update, including a full discussion, will be posted on Sunday, April 15.

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Drought Update: The next, and perhaps only, chance of widespread rain for the area is on Saturday night, when a wave of light to moderate rain will move through, with at least 1/4 inch of rain expected, although it will not be enough to ease the drought. Breezy SW winds will develop on Saturday and Sunday, with SW/SSW winds on Monday gusting up to 30-35 mph. The next cold front will move through around Tuesday, with the possibility of some rain towards the second half of next week along with lighter winds, although at least at this time, there does not appear to be a high probability of significant rain. The risk of brush fires will continue through the first half of the week, possibly into the second half as well if the ECM is incorrect with a very wet mid week storm, which it is currently the only model to show rain in that time frame and is an unlikely scenario at this time.

Forecast Overview:

- Mostly sunny skies will continue today and through the first half of Saturday, with highs today reaching the lower to mid 60s across most of the area and the upper 60s to mid 70s tomorrow. Cloud cover will increase by tomorrow evening.

- Occasional showers are expected on Saturday night, especially after 10 PM, through Sunday morning. No significant rain is expected, with up to 1/4 inch expected to fall. Partly cloudy skies will return on Sunday with highs reaching the mid to upper 70s from NYC and north/west, and the upper 60s to mid 70s in Long Island/CT.

- The warmest temperatures are expected on Monday; with breezy SW winds, 850mb temps near 15C, partly/mostly sunny skies and dry conditions, temperatures will rise into the 80s across most of the area, with highs reaching the mid to upper 80s from NYC and further north/west. With these conditions, the possibility is there that parts of the immediate NYC area, especially near NE NJ, reach 90 degrees. Upper 70s to mid 80s are expected in Long Island/southern CT except for the immediate coast, which will be cooler.

- A dry cold front will move through on Tuesday, with isolated showers possible overnight and into Wednesday. Highs will cool down back into the 60s for Wednesday/Thursday, although temperatures could warm up towards next weekend along with the next rain chance.

Wednesday, April 11, 2012

- No relief in drought soon; fires to continue across area- Next chance of light rain on Sunday, Tuesday- Windy conditions to return by weekend

Fire Updates:

Over the last two days, with the scattered showers once again failing to affect the area with more than light rain in some areas and nothing in other areas, as well as breezy winds, fires continued to spread across the area, with a large fire near the Meadowlands in NJ, affecting much of northeastern NJ with some sources stating that the fires were visible in Manhattan. Another notable fire also took place in Suffolk county.

Short Term Forecast: There is no relief in terms of rain for the drought for the short term through Sunday other than a few isolated showers tomorrow, and at this rate, the next US Drought Monitor update tomorrow (Thursday) is likely to show increasing drought conditions across the region. Winds, however, will briefly decrease as a high pressure moves in; NNW winds gusting up to 20-25 mph are expected on Thursday, with light NW winds on Friday. These lighter winds should bring some relief, although sunshine and lower humidity will return on Friday.

6-Day Forecast:

Tomorrow will end up slightly warmer, with highs in the mid-upper 50s, along with a risk of isolated light rain showers again. Friday will be mostly sunny with highs warming into the low-mid 60s across most of the area, with mostly sunny skies on Saturday and highs warming into the upper 60s-low 70s from NYC and north/west with 60s closer to the coast. Windy conditions will return on Saturday, however, with SW winds gusting up to 30-40 mph possible again.

Uncertainty returns to the forecast by Sunday as a ridge builds into the region for the first time since the big mid March warm spell, with the front end rain once again staying mostly to the north of the area, although some light rain is expected on Saturday night into Sunday morning, less than 1/4 inch. The area is expected to be in the warm sector on Sunday, with breezy WSW/SW winds and highs reaching the mid to upper 70s from NYC and further north/west, along with mid 60s to mid 70s in Long Island/southern CT. In the warmer case scenario with more clearing in the cloud cover by the afternoon, parts of northern NJ and areas near NYC may reach 80 degrees.

By Monday, a back door cold front will drop into the region, although it is uncertain whether it reaches the area or not. Interestingly, the GFS drops it through, with highs staying in the 60s to low 70s on Monday and Tuesday with a sharp temperature gradient south of the area, while the ECM and CMC keep the area in the warm sector, with highs reaching the 80s away from the coast on both days. With a strong low pressure modeled near Newfoundland on the GFS, the back door cold front would move through the area in that scenario, although the other models are much weaker with this feature, and the GFS is also trending weaker with this. At this time, I expect the cold front to end up close to the area but to the north, keeping the area in the warm sector. Although the extent of the warmth was a bit questionable on April 11th, as of the morning of 4/12 it appears that the trend is likely a correct one, and temperatures have been revised upwards to show 80s for Sunday through Tuesday.

The rain outlook is not looking very positive; with the front end rain staying mostly to the north on Saturday night and the back door cold front failing to move through, the next potential for more than light rain will be around Tuesday or Wednesday when the next cold front moves through, ending the warm spell, although the majority of the rain is expected to stay to the north of the area once again.

Monday, April 9, 2012

Wildfire Situation:After today's windy conditions, with gusts up to 40-45 mph across a large part of the area, along with dry conditions once again, wildfires became more widespread across the region, with many wildfires, some large, in places such as Long Island and New Jersey. Mostly cloudy skies are expected for tomorrow through Tuesday with scattered showers and lighter winds, which should offer some relief, although breezy conditions are still expected at times, with west winds on Tuesday and NW winds on Wednesday/Thursday, with only light rain amounts at most, amounting up to at least 0.1 to 0.2 inch locally while other places fail to see any rain. Temperatures will remain in the 50s, climbing up to the low 60s near NYC on Friday.

Longer Range: The next risk of rain will be during next weekend with the next brief warm surge as the trough temporarily weakens and moves out. There is some uncertainty on the exact intensity of the warm surge, although after yesterday's exaggerated warm scenarios on the ECMWF model, the models have backed down to a more reasonable 1-2 day warm surge, with temperatures reaching the 70s in parts of the area with a risk of rain for Sunday and Monday. Once again, this does not appear to be a very moist storm, although the latest models show two rounds of rain: Light to moderate rain early on Sunday with the warm front, and rain and possible thunderstorms on Monday with the cold front. Any rain at this time will be a relief to the developing drought conditions, and although the rain outlook is still subject to change, it still does not appear to be a very wet storm. Windy conditions may perhaps return for this time frame as well. Stay tuned for more information on the longer range outlook.

Sunday, April 8, 2012

Reminder: This blog is still on vacation. Occasional brief updates will be posted, and the next full update will be posted on Sunday, April 15.

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Forecast Overview: As a strong trough continues to move into the region, the longest lasting of the entire season despite it taking place in April, temperatures will remain near to below average through most of this upcoming week. A strong cutoff low moved into Maine earlier today, and is stalling in that region, trapping a chilly air mass over the region through at least Thursday. The trough is likely to exit with a returning warm air mass by next weekend and the following week, but it is too far out to tell exactly how warm it will be and how much rain will fall.

Monday - Thursday: Temperatures will remain mild tomorrow, with highs reaching the lower to mid 60s across the area, passing 65 degrees near the immediate NYC area, which is slightly warmer than average. Windy conditions are expected as well, with gusts up to 40-45 mph expected across the area, and the risk of fires developing is still present across the area, especially with the wind and the dry conditions recently observed; the latest U.S. Drought Monitor update as of Thursday placed almost all of southern New England, including Connecticut and Long Island, under moderate drought conditions.

A weak low pressure will develop offshore during the mid-late week period, with partly-mostly cloudy skies and a risk of isolated showers between Monday night and Thursday. Any shower, however, is expected to remain light, with no decent rain amounts expected. Temperatures will be below average in this time frame, reaching the lower to mid 50s inland and mid to upper 50s elsewhere on Tuesday and Thursday, with Wednesday likely the colder day, with highs in the upper 40s to lower 50s inland and lower to mid 50s across the rest of the area.

Longer Range: There is a strong signal on almost every model for a ridge to develop with a strong warm air mass spreading east. There is still uncertainty, however, regarding how far north the warmth extends, as models such as the GFS and CMC keep the area near the northern boundary of the warm air mass, bringing several waves of beneficial moderate-heavy rain through the region while keeping temperatures in the 60s and 70s. The ECM is currently the most bullish with the warmth, spreading it much further north. Given the trends under this new pattern, I am leaning towards the GFS/CMC with a weaker warm air mass further south, keeping temperatures in the area mostly in the mid-upper 60s with some days passing 70 degrees, along with a higher risk of widespread rain falling in the region, either near or north of the area. There is still uncertainty with this, however, and it is possible that a warmer scenario could verify, in which case temperatures would be much closer to 80 degrees with a lower widespread rain risk for the area. More information will be posted with additional brief updates this week.

Thursday, April 5, 2012

Between April 6-13, this blog is going on vacation. Brief updates will be posted on occasions, especially when stormy weather is possible. The next full update will be posted on Sunday, April 14.

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Forecast Highlights:

- Colder pattern continues; near-below average temps next week- Mostly dry conditions continue, some light rain next week- Breezy winds expected this weekend, early week- Temperatures may warm up by end of next week/next weekend

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As yet another chilly air mass moved into the area, temperatures today were colder than those of yesterday. High temperatures reached the mid 50s in northwestern areas inland, upper 50s to lower 60s in the immediate NYC area, and the mid to upper 50s in Long Island and southern CT. Since the big March warm spell, a cooler pattern developed across the region, with temperatures dropping down to near average levels, ending up below average on some occasions. While there is uncertainty with exactly how long the pattern lasts, it will continue to be in place through at least most of next week.

Tomorrow's Outlook:

Tomorrow will bring mainly sunny skies across the area with light NW winds expected. Temperatures will be similar to those of today, reaching the mid to possibly upper 50s inland, upper 50s to lower 60s in the immediate NYC area, and mid to upper 50s in Long Island and southern CT.

Weekend Outlook: Slightly Warmer

Mainly sunny skies will continue through the weekend as well, with temperatures slightly warming up but still remaining close to the average. Highs are expected to reach the mid 50s to lower 60s across the area on Saturday, with widespread lower to mid 60s on Sunday. Breezy winds are expected for both days with gusts up to 30, locally 35-40 mph, possible.

Next Week: Chilly Pattern Continues

A weak low pressure currently in the southern US will move east and offshore this weekend, as many of this winter's storms have done. Unlike the rest of these storms, however, the storm will be blocked from moving northeast, and will strengthen while retrograding towards Maine, moving from east to west through Nova Scotia and New England before stalling over the region. This is the result of a weak blocking pattern that has developed with more ridging near Greenland; this type of pattern, should it have taken place during the winter, would have easily been supportive of sustained cold and snow, but by the time the stubborn and long lasting warm pattern observed in the winter fell apart, doing so in mid March, it was already too late for winter to return to the NYC area. As a result of this, a trough will once again lock itself over the region for most of next week, with chilly temperatures expected to continue, ending up near to below average, with a few light rain possibilities.

Partly to mostly cloudy skies are expected on Monday as the low pressure moves into southeastern Canada, with a stronger west/WSW expected for the area; gusts have the potential to reach and/or exceed 40 mph across parts of, if not most of the area. Temperatures will be similar to those of Sunday, reaching the lower to mid 60s for most places north/west of NYC and the mid 50s to lower 60s in Long Island/southern CT. Some showers are possible on Monday night as light precipitation moves through, with Tuesday bringing partly to mostly cloudy skies and highs reaching the lower to mid 50s inland and the mid to upper 50s across the rest of the area. Breezy winds are expected again on Tuesday but with less wind compared to Monday.

There is some more uncertainty for the middle of next week as the GFS keeps the area dry while the ECM has more rain and keeps the trough amplified through next week. At this time, I am leaning closer to the drier GFS, with the ECM possibly overdoing the amplification of the trough, with some light rain possible again on Wednesday, although no significant rain is expected at any time next week; most of the time frame is likely to be dry for the area. Temperatures will depend on the rain probability and the exact location of the low pressure to the north, although temperatures are still expected to stay in the 50s across the area.

Longer Range / Rest of April Outlook: Uncertainty increases beyond the middle of next week due to the time range, although despite signs of the blocking weakening, the chilly pattern is not expected to reverse to a warm one. The warm pattern that has brought persistently significant positive temperature departures across the region has likely ended with the warm spell in mid March; troughs have become more frequent in the region, warm spells in the central US struggle to reach the region, and ridging is showing up more often near Greenland. While a warmer second half of the month is expected compared to the first half of the month, temperatures are still expected to remain relatively close to average, leaning towards warmer than average. There could still be some warm days, but given the pattern they would more likely be in the form of 1-2 day warm surges as opposed to prolonged warm spells. Overall, April is expected to end up only slightly warmer than average across the area, as opposed to the last few months which were much warmer than average, especially March which was the 2nd warmest March on record. The warmest departures will remain in the central US. April is also expected to feature below average precipitation.

As mentioned in the start of the post, this will be the last full update until April 14. Until then, occasional brief updates will be posted, including updates on the forecast for next week as well as the longer range.

Pattern Outlook: A trough will move into the region tonight and tomorrow, and will not leave until late next week at the earliest. Changes in the pattern, including the development of blocking near Greenland that has failed to develop throughout the entire winter, is resulting in a colder pattern for the region; had this pattern developed 2 months ago, it would have easily produced snow for the area, but given the time of the year, it's too late for the pattern change to produce snow in the area. The trough will slightly weaken by Saturday/Sunday, resulting in temperatures ending up near-slightly above average, but as a strong low pressure retrogrades into Maine, the trough will intensify over the region, with the possibility for a weak storm to affect the area around the middle of next week. Temperatures will remain near to below average through parts of, if not most of next week, with temperatures likely warming by the end of next week. More information on the long range beyond this will be posted with an April overview in the Long Range Forecasts page with Thursday's update.

Thursday - Monday: Mostly sunny skies will continue in this time frame. Highs will reach the mid to upper 50s on Thursday and Friday, and the upper 50s to lower 60s on Saturday. Warmer temperatures are expected on Sunday and Monday as the cutoff low moves into Maine and the cold air mass approaches the area, with highs reaching the upper 50s to lower 60s again, with mid 60s near NYC. Breezy winds are possible on Monday.

Tuesday - Friday: The chilly air mass will be in place during this time frame, with below average temperatures expected. Highs are likely to generally end up in the lower to upper 50s, with lows in the mid to upper 30s inland and the upper 30s to mid 40s across the rest of the area. Should a weak coastal low form, it will likely do so around Tuesday, when more clouds are expected with slightly cooler temperatures along with a risk of showers, although at least as of now it does not appear that such a storm would produce heavy rain for the area; heavier rain is a possibility, but at this time does not have much support. Temperatures are likely to warm up by the end of next week and towards next weekend as well, but it does not appear that more sustained above average temperatures will be quick to return.

Monday, April 2, 2012

- Highs in mid 50s to low 60s, dry conditions continue this week- Little warmer by Sunday/Monday, a little rain, then back to same pattern

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Note: With the sudden change in the pattern, the post-winter analysis, originally planned for this week, has been delayed to account for another part of the summary comparing the winter pattern to the pattern that has recently developed. By the end of April, I will post a detailed analysis of this winter, reflecting some reasons that caused it to end up mild with almost no snow, along with verification of the winter outlooks.

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With another back door cold front moving into the area behind yesterday's weak rainstorm, temperatures ended up seasonable across the area, with partly sunny skies, breezy winds, and highs reaching the mid to upper 50s. With a weak blocking pattern near Greenland keeping troughs stuck over the region through the end of this week, little changes are expected in the pattern, with temperatures staying in the mid 50s to lower 60s through Saturday along with dry conditions. A brief warm up is expected towards the weekend and possibly Monday, although seasonable temperatures are likely to return again towards the middle of next week.

Forecast Overview:

With the pattern still the same, there are little changes in the expectations for this week and the weekend. Highs are expected to reach the upper 50s to lower 60s on Tuesday with mostly sunny skies, with partly sunny skies and similar temperatures for Wednesday. An isolated shower may be possible on Tuesday night, but no widespread rain is expected. Mostly to partly sunny skies then return for the rest of the week with highs reaching the lower to mid 50s on Thursday, mid to upper 50s on Friday with 60 degrees possible near NYC, and upper 50s to lower 60s on Saturday with mid 60s near NYC.

As a cold front approaches for Sunday and Monday, winds will turn towards the south/SSE as a warm air mass briefly moves through, with temperatures reaching the lower to mid 60s from NYC and further north/west, passing 65 degrees in parts of northern NJ/SE NY, and the 50s to low 60s in Long Island and southern CT. Despite model differences with the location and timing of the cold front, it does not appear to be a wet one, with light rain possible towards Monday. Uncertainty increases due to the time range going later into next week, but seasonable temperatures are likely to return after the weak cold front.

After the storm two nights ago and yesterday's chilly temperatures, with highs only ending up in the 40s across the area, March ended up as the 2nd warmest March on record in NYC; the storm on the night of 3/30 increased the rain totals across the area, and this year's March was the 4th driest March on record with 0.96 inch of rain; the driest March was 2006 with 0.80 inch. Slightly warmer temperatures were observed today, reaching the upper 40s to mid 50s across the area, although today's temperatures were still colder than average.

The latest radar posted above shows that the round of moderate rain that affected the area this evening has moved to the south and east; other than a few showers, the rain is over for tonight, marking the start of another week of dry conditions. As temporary blocking near Greenland continues to keep a chilly air mass stuck over the Northeast, the warm spells and stormy weather affecting the central US will still be suppressed south of the area, keeping NYC with seasonable temperatures and dry conditions this week; the next chance of rain is not until at least 4/9, which will be accompanied by a brief warm surge.

Tomorrow's Outlook

As the current warm spell in the Midwest shifts further east, it will be forced south as another back door cold front approaches the region. As a result, temperatures will warm up tomorrow, reaching the lower to mid 50s across the area with some upper 50s near NYC, which is close to the average for this time of the year. Partly sunny skies are expected along with breezy conditions, with N/NNW winds gusting up to 35-40 mph.

Tuesday - Beyond: Back To Seasonable, Dry Pattern

There is not much to say about the mid to late week time frame other than that seasonable and dry conditions will continue. Tuesday and Wednesday will slightly warm up with partly cloudy skies, reaching the upper 50s to lower 60s across the area with parts of NE NJ getting close to 65 degrees. Isolated showers are possible on Tuesday night but most places will stay dry. Another trough will move in on Wednesday and will remain stuck over the region through at least Saturday, with temperatures in the late week through Saturday reaching the mid to upper 50s across the area with lower 60s near NYC on Friday and Saturday. Mostly to partly sunny skies are expected for the late week and Saturday.

Going into Sunday and early next week, most models bring in a short lasting warm surge. Unlike the last time this was modeled, which was for Monday when most models had a strong warm surge which due to the strong back door cold front will not reach the area, the pattern for Sunday and Monday does not appear to support a back door cold front coming through, and with a high pressure dropping through the region, at least a 1-2 day period of SW/SSW winds is possible, which will likely result in a 1-2 day warm surge for the region. Temperatures in this time frame are expected to return into the mid to upper 60s especially north/west of NYC, and depending on the timing of any approaching cold front towards the early week, temperatures may reach the 70s in parts of the area. There is more uncertainty regarding the potential for a cold front to approach, although at this time it does not appear that any moderate-heavy rain should fall out of the potential cold front.

6:35 PM: The second widespread rain event over the last few days is affecting the area, with occasional showers expected to last through the first half of the overnight hours. A strong rain squall is currently located near northeastern NJ, producing widespread heavy rain, and will move through NYC and the western half of Long Island over the next 1/2 hour. Radar estimations show that these storms are capable of producing 1/4 inch of rain in a short period of time.